Numerical and Experimental Study of Unsteady Flow in a Large Centrifugal Pump With Stay Vanes

2014 ◽  
Vol 136 (7) ◽  
Author(s):  
Zhongxin Gao ◽  
Wenruo Zhu ◽  
Li Lu ◽  
Jie Deng ◽  
Jianguang Zhang ◽  
...  
Keyword(s):  
Experimental Data ◽  
Unsteady Flow ◽  
Centrifugal Pump ◽  
Pressure Fluctuations ◽  
Rate Variation ◽  
Operation Condition ◽  
Calculation Results ◽  
Static Performance ◽  
Steady Simulation ◽  
Comparison Of The Results

The unsteady flow inside a large centrifugal pump with stay vanes was analyzed in this study. The static performance and pressure fluctuations in the pump were numerically predicted and were compared with experimental data. Considering the relative positions of the impeller to the volute tongue and stay vanes, the static performance which was obtained using a full unsteady calculation was compared with traditional steady calculation results. A comparison of the results with the experimental data showed that the operation condition farther from the design condition resulted in larger differences between the steady simulation and experimental results, with errors beyond reasonable limits, while the performance curves obtained by the unsteady calculations were closer to the experimental data. A comparison of the pressure fluctuations at four monitoring points with the experimental data showed that the amplitudes at HVS1 and HVS2 are much larger than at HD1 and HD2. The main frequency for these four monitoring points, which agreed well with the experimental data, was the blade passing frequency. The relative obvious errors in pressure fluctuations for HD1and HD2 were due to the inlet flow rate variation of the simulation. Thus, unsteady numerical simulations can be used to predict the pressure fluctuations when designing a pump.

Relationship Between Unsteady Flow, Pressure Fluctuations, and Noise in a Centrifugal Pump—Part B: Effects of Blade-Tongue Interactions

1995 ◽  
Vol 117 (1) ◽  
pp. 30-35 ◽  
Author(s):  
S. Chu ◽  
R. Dong ◽  
J. Katz
Keyword(s):  
Unsteady Flow ◽  
Centrifugal Pump ◽  
Pressure Difference ◽  
Pressure Fluctuations ◽  
Primary Sources ◽  
Pressure Measurements ◽  
Local Pressure ◽  
Pressure Distributions ◽  
Flow Pressure ◽  
Tip Of The Tongue

Maps of pressure distributions computed using PDV data, combined with noise and local pressure measurements, are used for identifying primary sources of noise in a centrifugal pump. In the vicinity of the impeller pressure minima occur around the blade and near a vortex train generated as a result of non-uniform outflux from the impeller. The pressure everywhere also varies depending on the orientation of the impeller relative to the tongue. Noise peaks are generated when the pressure difference across the tongue is maximum, probably due to tongue oscillations, and when the wake impinges on the tip of the tongue.

Influence of wall roughness on the static performance and pressure fluctuation characteristics of a double-suction centrifugal pump

2018 ◽  
Vol 232 (7) ◽  
pp. 826-840 ◽  
Author(s):  
Zhifeng Yao ◽  
Min Yang ◽  
Ruofu Xiao ◽  
Fujun Wang
Keyword(s):  
Centrifugal Pump ◽  
Pressure Fluctuation ◽  
Pressure Fluctuations ◽  
Design Flow ◽  
Experimental Investigations ◽  
Wall Roughness ◽  
Detached Eddy Simulation ◽  
Centrifugal Pumps ◽  
Eddy Simulation ◽  
Static Performance

The unsteady flow field and pressure fluctuations in double-suction centrifugal pumps are greatly affected by the wall roughness of internal surfaces. To determine the wall roughness effect, numerical and experimental investigations were carried out. Three impeller schemes for different wall roughness were solved using detached eddy simulation, and the performance and pressure fluctuations resolved by detached eddy simulation were compared with the experimental data. The results show that the effects of wall roughness on the static performance of a pump are remarkable. The head and efficiency of the tested double-suction centrifugal pump are raised by 2.53% and 6.60% respectively as the wall roughness is reduced by means of sand blasting and coating treatments. The detached eddy simulation method has been proven to be accurate for the prediction of the head and efficiency of the double-suction centrifugal pump with roughness effects. The influence of the roughness on pressure fluctuation is greatly dependent on the location relative to the volute tongue region. For locations close to the volute tongue, the peak-to-peak value of the pressure fluctuations of a wall roughness of Ra = 0.10 mm may be 23.27% larger than the case where Ra = 0.02 mm at design flow rate.

3D Quasi-Unsteady Flow Simulation in a Centrifugal Pump: Comparison With the Experimental Results

2004 ◽  
Author(s):  
Miguel Asuaje ◽  
Farid Bakir ◽  
Andres Tremante ◽  
Ricardo Noguera ◽  
Robert Rey
Keyword(s):  
Unsteady Flow ◽  
Centrifugal Pump ◽  
Cfd Simulation ◽  
Pressure Fluctuations ◽  
Pressure Sensors ◽  
Flow Simulation ◽  
Turbulence Models ◽  
Numerical Predictions ◽  
Radial Thrust ◽  
Unsteady Flow Simulation

A 3D-CFD simulation of the impeller and volute casing of a centrifugal pump has been performed using commercial codes CFX 5.5 and CFX-TASCflow 2.12. The pump has an specific speed of 32 (metric units) and an outside impeller diameter of 400 mm. First, a 3D-flow simulation for the isolated impeller with a structured grid is presented. A sensitivity analysis regarding grid quality and turbulence models were also performed. A 3D quasi-unsteady flow simulation of the impeller-volute assembly is presented, as well. This flow simulation was carried out for several impeller blades and volute tongue relative positions. As a result, the radial thrust on the pump shaft were calculated for different flow rates. Experimental test were carried out in order to compare theoretical pressure fluctuations with the experimental ones measured by various unsteady pressure sensors placed on the impeller shroud and volute. The qualitative and quantitative results ratify numerical predictions.

Numerical investigation of influence of inlet guide vanes on unsteady flow in a centrifugal pump

2015 ◽  
Vol 229 (18) ◽  
pp. 3405-3416 ◽  
Author(s):  
Wang Yuchuan ◽  
Tan Lei ◽  
Zhu Baoshan ◽  
Cao ShuLiang ◽  
Wang Binbin
Keyword(s):  
Unsteady Flow ◽  
Centrifugal Pump ◽  
Pressure Fluctuations ◽  
Turbulence Models ◽  
Rotational Frequency ◽  
Pump Impeller ◽  
Guide Vanes ◽  
Pump Performance ◽  
Inlet Guide Vanes ◽  
Dominant Frequencies

The influence of inlet guide vanes on unsteady flow in a centrifugal pump is numerically investigated. The independences of mesh elements, time steps and turbulence models are studied, and the satisfactory agreement between experimental and numerical results of the centrifugal pump performance validates the reliability and accuracy of the numerical model. The frequency characteristics of pressure fluctuations in impeller and volute are nearly the same for the pump without and with inlet guide vanes in the angle range from −36° to +36°. In the pump impeller, the dominant frequencies are mainly the rotational frequency fi (24.17 Hz) or 2 fi, and in volute they are the blade passing frequency fBPF (145 Hz). For the large inlet guide vanes angles of −60°and +60°, the maximum amplitudes of pressure fluctuations in pump impeller and volute are stronger than that in pump without inlet guide vanes. Therefore, the influence of inlet guide vanes on unsteady flow in the centrifugal pump is slight when the inlet guide vanes angles are regulated in a suitable region.

A Study of Flow Analysis for a Double-Suction Centrifugal Pump

2002 ◽  
Author(s):  
Kyung-Nam Chung ◽  
Pyun-Gu Park ◽  
Hyun-Joon Cho ◽  
Sang-Gu Lee
Keyword(s):  
Experimental Data ◽  
Centrifugal Pump ◽  
Flow Rate ◽  
Pressure Field ◽  
Flow Analysis ◽  
General Performance ◽  
Pump Head ◽  
Calculation Results

Flow analysis was carried out for a double-suction centrifugal pump. An impeller-only model and a full pump model were used to simulate the velocity and the pressure field of the pump. Pump head and efficiency were calculated with flow rate in order to obtain general performance of the pump. The calculation results were compared to the experimental data, and satisfactory results were obtained. Also, the velocity and the pressure field of this pump were analyzed for the rated point and off-design points. Changes of the velocity and the pressure field with flow rate were investigated at impeller eye and impeller exit.

scholarly journals Numerical Study of Pressure Fluctuation and Unsteady Flow in a Centrifugal Pump

Processes ◽  
2019 ◽  
Vol 7 (6) ◽  
pp. 354 ◽  
Author(s):  
Ling Bai ◽  
Ling Zhou ◽  
Chen Han ◽  
Yong Zhu ◽  
Weidong Shi
Keyword(s):  
Unsteady Flow ◽  
Centrifugal Pump ◽  
Pressure Fluctuation ◽  
Static Pressure ◽  
Numerical Study ◽  
Pressure Fluctuations ◽  
Flow Patterns ◽  
Lower Number ◽  
Centrifugal Pumps ◽  
Impeller Blade

A pump is one of the most important machines in the processes and flow systems. The operation of multistage centrifugal pumps could generate pressure fluctuations and instabilities that may be detrimental to the performance and integrity of the pump. In this paper, a numerical study of the influence of pressure fluctuations and unsteady flow patterns was undertaken in the pump flow channel of three configurations with different diffuser vane numbers. It was found that the amplitude of pressure fluctuation in the diffuser was increased gradually with the increase in number of diffuser vanes. The lower number of diffuser vanes was beneficial to obtain a weaker pressure fluctuation intensity. With the static pressure gradually increasing, the effects of impeller blade passing frequency attenuated gradually, and the effect of diffuser vanes was increased gradually.

The Numerical Calculation of Static Performance of Multi Wound Foil Bearing and Experimental Validation

2007 ◽  
Author(s):  
Kai Feng ◽  
Shigehiko Kaneko
Keyword(s):  
Numerical Calculation ◽  
High Speed ◽  
Load Capacity ◽  
Convergence Criterion ◽  
Operation Condition ◽  
Foil Bearings ◽  
Deformation Equation ◽  
Experimental Apparatus ◽  
Calculation Results ◽  
Static Performance

Multi wound foil bearings (MWFB), as a kind of foil bearings with simple structures, are supposed to be one of the best candidates of supporting component for turbo-machineries because of their design simplicity, reduced weight and size, high speed and temperature capability, and easy maintenance. In this study, a theoretical model of MWFB taking account of the effect of the foil deformation is developed to predict its static performance. Reynolds’ equation is solved using Finite Difference Method (FDM) to yield air pressure distribution, while the elastic deformation equation is solved by Finite Element Method (FEM) to predict the deformation of the foil. Then, the above two equations are coupled by several iterations until the convergence criterion is reached. Based on the calculations, static characteristics of MWFB such as film thickness, load capacity and torque are presented. Finally, an experimental apparatus is built up to measure the load of MWFB at different operation condition, which are used to validate numerical calculation results.

Effects of Splitter Blades on the Unsteady Flow of a Centrifugal Pump

2012 ◽  
Author(s):  
Liting Ye ◽  
Shouqi Yuan ◽  
Jinfeng Zhang ◽  
Ye Yuan
Keyword(s):  
Flow Field ◽  
Unsteady Flow ◽  
Numerical Simulations ◽  
Centrifugal Pump ◽  
Pressure Fluctuations ◽  
Internal Flow ◽  
Suction Side ◽  
Boundary Function ◽  
Wake Flow ◽  
Design Parameters

Numerical simulations and performance tests were conducted to analyze the effects of splitter blades on the performance and whole unsteady flow field of a centrifugal pump. The studied pump is a single stage pump with a shrouded impeller (diameter = 160mm, 4 blades, specific speed = 47). Based on the original impeller, we designed 5 impellers with different splitter blades parameters. All the numerical simulations were carried out by using the commercial software ANSYS CFX 12.1 based on standard k-ε turbulence model and standard boundary function. The results showed that, the head of the impellers with splitter blades was approximately 2%∼12% higher than that without splitter blades. When adding splitter blades, the pressure fluctuations at the impeller inlet, volute outlet and the interface of impeller and volute are reduced, this can improve the “jet-wake” flow structure. Different design parameters of splitter blades have a certain effect on the pressure fluctuations at the interface of impeller and volute. When the splitter blades deviated 5° to the suction side of the long blade and the splitter blade inlet diameter is 106 mm, the head is highest and the pressure fluctuations are lowest. The work will provide a basis for the further study on the internal flow field, reducing vibration and noise of a centrifugal pump.

Theoretical Study of Pressure Fluctuations Downstream of a Diffuser Pump Impeller—Part 2: Effects of Volute, Flow Rate and Radial Gap

1997 ◽  
Vol 119 (3) ◽  
pp. 653-658 ◽  
Author(s):  
W. Qin ◽  
H. Tsukamoto
Keyword(s):  
Experimental Data ◽  
Unsteady Flow ◽  
Flow Rate ◽  
Theoretical Study ◽  
Pressure Fluctuations ◽  
Leading Edge ◽  
Trailing Edge ◽  
Pump Impeller ◽  
Impeller Blade ◽  
Radial Gap

The fundamental analysis in the first report was extended to calculate the unsteady flow induced by the interaction between impeller blades and diffuser vanes/volute casing in a diffuser pump. The unsteady flow in the diffuser vane passage, as well as the volute casing, is assumed to be induced by the five kinds of singularities—the bound vortices distributed on the impeller blades, diffuser vanes and volute casing wall, the sources at volute outlet, and the free vortices shed from the trailing edge of diffuser vanes. Calculated unsteady pressures agree with the corresponding experimental data. And the calculated results showed the effects of the flow rate, volute casing and the radial gaps between impeller blade trailing edge and diffuser vane leading edge on the magnitude of unsteady pressure downstream of impeller.

Unsteady Flow Modeling Using Transient Rotor–Stator Interface

2013 ◽  
Author(s):  
Rudolf A. Izmaylov ◽  
Henry D. Lopulalan ◽  
Gertruida S. Norimarna
Keyword(s):  
Experimental Data ◽  
Unsteady Flow ◽  
Turbulent Flows ◽  
Reasonable Agreement ◽  
Full Range ◽  
Three Dimensional ◽  
Time Discretization ◽  
Rotating Stall ◽  
Flow Phenomena ◽  
Calculation Results

Based on experimental investigation of unsteady flow phenomena in centrifugal compressor, conducted in LPI (SPbSPU), including the measurements of high frequency pressure and hot-wire probes, numerical calculation was conducted with the aid of commercial ANSYS CFX12. The object was a model of industrial compressor, tested in full range of mass flows (from maximum to the onset of surge). Unsteady turbulent flows were calculated with URANS, turbulence model - SST-Menter. Region between the impeller and diffuser was calculated with Transient Method option. Time discretization Δ = 12 μsec. Sequential 20 revolutions of rotors were calculated, also LES model were used. Unsteady calculation results demonstrated reasonable agreement with experimental data both in meridional, and radial sections concerning the character of “jet – wakes” propagation, distribution of velocities in diffuser, and clearly showed three-dimensional flow conditions and reverse zones on the diffuser walls. “Frozen” velocity distributions during rotating stall demonstrated possibility of unsteady flow prediction with the aid of ANSYS CFX12. CFD results comparison with experimental data showed reasonable agreement for distributions of total pressures in diffuser, as well total and static characteristics of impeller and diffuser.

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